Radio tuner



NOV. 14, 1933. LESH 1,934,722

RADIO TUNER Original Filed July 10, 1924 M QM /NVENTOR.

A T TOR NEY5 Patented Nov. 14, 1933 I PATENT" oF-Fics RADIO TUNER Laurence J. Lesh, Chicago, Ill., assignor, by mesne'assignments, to Associated Electric Laboratories, Inc., Chicago, 111., a corporation of Delaware Application July 10, 1924, Serial No. 725,216 Renewed May 25, 1928 23 Claims.

101 The-tuning of radio apparatus is generally accomplished by variations of capacity and inductance. Well known devices for this purpose are the variable condenser for changing capacity and the variometer for changing inductance. Vari- 1'53 ometers and variable condensers are usually operated by the rotary movement of shafts requiring independent manual manipulation. It is not suilicient to attach the rotary element of both a variometer and variable condenser to the same '20: shaft. This permits their simultaneous operation but with the limitation and disadvantage that the units cannot be individually operated or controlled independently of each other.

The main objects of my invention are to siml plify the adjustment and control of electrical apparatus including inductance and capacity units; to provide for simultaneous adjustment of both of these factors by means of one control handle; to so connect such diverse units to a common control member that one will be adjusted by a thrust action and the other by a twist movement; and to provide a semi-automatic adjust ment of reaction or feedback in and-ion circuits during the process of tuning and to combine a My invention largely eliminates the necessity of aseparate adjustment of the reaction coupling to take care of changes in resistance of a grid circuit due to changing LC ratio of a capacity 40 tuned circuit and varying absorption at diiierent wave-lengths introduced by a circuit coupled to the grid circuit.

With these ends in view, my invention utilizes both an axial and a rotary movement of a shaft having a suitable control handle or knob attached to it, so that, for example, the rotary movement may control a variable capacity while the axial movement controls a variable inductance. By suitable mechanical means, I so arrange the capacity and inductance that they may be varied simultaneously or individually and so that the simultaneous change may be at either a fixed or variable rate or ratioof capacity to inductance.

In carrying out my idea lutilize what might rotary and axial movement of a control shaft;

be termed an electrical cam, which for given increments of capacity variation provides approximately correct changes of reaction coupling from plate to grid circuit so as to substantially maintain an audion circuit on thepoint of oscillation or at a definite point of reaction, in spite of changes in electrical periodicity of a grid circuit.

As a typical example of tuning, I have obser ed that a grid inductance, tuned by a shunt variable condenser, suliers absorption at its lower wavelength range when inductively related to an aperiodic antenna circuit of a lower natural period than the reoeivedoscillations and therefore requires more reaction from a plate circuit, while at the middle range of capacity tuning, less reaction is required and again at thepoint of maximum capacity a greater reaction is required to overcome the resistance of the grid circuit to oscillation. My invention. automatically corrects deficiencies and accommodates the major reaction requirements with final manual adjustment utilizing thesame control knob employed for capacity tuning changes.

The desired result is attained by combining a rotative and axially moving control shaft actuating a rotary variable condenser and an inducttance of special form which may be both rotated and moved axially in relation to a coil adjustably fixed in axial and rotative position. The coils are employed in a reaction coupling which varies in amount with changes in their relative rotative position and distance apart. The dis tance apart or axial movement is at all times under manual control. The disposition of the coils may be adjusted so that for a continuous change of capacity obtained by the variable condenser, predetermined increments of reaction are automatically provided with a final manual correction of reaction.

In the construction shown by the drawing, Fig. 1 is mainly a perspective view of the device, with wiring and circuit connections shown conventionally, and the adjusting guide member being re-, moved. Figure 2 is a detail viewshowing the handle guide and guide arm.

Referring to the drawing, Fig. 1 shows an embodiment of my invention with electrical connections to a reactive audion circuit symbolically represented. The construction of the tuner proper will now be described. B is a base or support of insulating material to which is securely mounted a metal end piece A having a boss J integral with it. This end piece A is perforated at A', forming a bearing for the rotative movement of; the hollow condenser shaft I to which are .at-

tached the condenser plates G and G. Members F and F are the fixed plates of the condenser held securely in the metal block E which in turn is secured to the insulating base B. Rod H is the main operating shaft axially movable within the concentric hollow shaft I of the variable condenser and yet communicating any rotary movement to the condenser by means of the key K set in shaft H and sliding in the slot or keyway L, of shaft 1.

Both axial and rotative movements of shaft H are controlled by the knob or handle Y attached to it. At its other extremity the shaft H is secured to a semi-circular insulating plate M, which has an inductance wound on either or both of its semi-circular segmental faces. In the present instance, the coil R is an aperiodic antenna inductance of few turns, one end of which is electrically connected at H to the shaft H and thence through the metal support A to ground, while the other end of coil R is connected to an oscillation collector or antenna S. On the opposite side of plate M is wound or mounted a coil B, one terminal of which also is connected to shaft H, will be understood, while the other terminal is connected to the grid wire T of an audion, employed in this case for the detection of radio oscillations. The fixed plates F and F of the condenser also are electrically connected to the grid wire T, there by placing the variable condenser in shunt with the grid or closed oscillating circuit.

The member X is a semi-circular insulating plate similar to plate M, having mounted on its face an inductance or coil N which is electrically connected as a reaction coil in the plate circuit of the audion assembly W, the connection being through the plate wire U and through the shaft 0 passing through the metal support D. The post members D and C are telescoping members of a column, supporting shaft 0 and the attached plate X. A setscrew P permits a longitudinal axial setting combined with a rotary setting of shaft 0, while setscrew Q controls the vertical elevation setting of shaft 0, and consequently the plate X attached to it.

In order to facilitate quick adjustment, a guide 2 and guide arm Z are preferably provided, though for some purposes they may be omitted. Said guide is formed with a spiral slot 3 adapted to serve substantially as a cam guide for the arm. Said guide is secured to support A by screws R, and the arm Z is secured detachably to knob Y.

With the movable elements in the position shown, it will be observed that the variable condenser is at the midpoint of capacity while the reaction coupling of plate to grid coils in the rotative sense is at a minimum. If the condenser is rotated to maximum or minimum capacity, an equal increase of reaction will occur. If the condenser is rotated 180 degrees, a maximum or full reaction will take place with again a midpoint of capacity. By various settings of the reaction coil N in axial, rotative and vertical position, with respect to coil mounting M in conjunction with manually operated axial movement of plate M by shaft H, a wide range of reaction possibilities is available, as will be apparent, to compensate for changes in tuning. As an example, it is possible, by lowering plate X until the axis of the magnetic field of coil N coincides with the rotative axis of plate M, to produce a substantially constant reaction effort while tuning. In this latter case the regulation of reaction would rest entirely with axial movement of the control shaft H attached to plate M. With the guide 2 and arm Z in place,

the operator merely moves the shaft H in and out, and the proper twist is imparted by said guide.

I have presented my invention as applied to the continuous regulation of reaction in tuning a conventional audion receiver. It is apparent that the invention may also be applied to interstage coupling of radio frequency amplifiers, and in fact, to any radio circuit transmitting or receiving, where the exact control of reaction is required. In radio frequency amplification, the circuit or coil R would function as the primary or plate inductance for inter-tube coupling.

Although but one specific embodiment of this invention is herein shown and described, it will be understood that numerous details of the construction shown may be altered or omitted without departing from the spirit of the invention as defined by the following claims.

I claim:

1. A radio tuner comprising a variable condenser and an adjustable inductance, in combination with a common operating means arranged and connected to adjust the condenser rotatively and to adjust the inductance by endwise movement of the common operating means.

2. A radio tuner comprising in combination a shaft adjustable rotatively and endwise, a variable condenser adapted and arranged for adjustment by rotation of said shaft and an inductance adapted and arranged for adjustment by endwise movement of said shaft.

3. A radio tuner adapted to accommodate infinitely fine gradual adjustment of wavelength, said tuner including a condenser device and an inductance device, each of adjustable character, and a shaft mounted for both rotary and endwise movement whereby adjustment of said devices may be effected simultaneously through a combination of said movements.

4. A radio tuner comprising a variable condenser and an adjustable inductance member appropriately connected electrically, in combination with a common operating shaft mounted to accommodate rotary and endwise movement, means to adjust the condenser rotatively and to adjust the inductance member by endwise movement.

5. A radio tuner comprising a shaft mounted for rotary and endwise adjustment in combination with a variable condenser operably connected to said shaft for adjustment by rotative movement of the latter, and an inductance member having a plurality of windings, one of which is adjustable by endwise movement of said shaft to vary the effect of said member.

6. A radio tuner comprising a variable condenser, a variable inductance and a shaft mounted for both rotary and endwise movement, said inductance including a stationary part, and a part movable relative thereto lengthwise of said shaft by endwise movement of said shaft, whereby the inductance may be varied, said condenser including a stationary part and a part co-rotatable with said shaft to which it is keyed for relative end- Wise movement as the shaft slides lengthwise.

'7. A radio tuner comprising a support, and mounted thereon a variable condenser and an adjustable inductance device appropriately connected electrically to said condenser, in combinaincluding apai'r of. segmental flattish windings, disposed crosswiseof" the axis of said operatingmeans, one-carried by said. holder and theother by said operating. means.

8% A radio tuner comprising an actuating'shaft capable ofi endwise movement .and rotation,. having a fixed radial member moving endwise in a,

j; and connected to adjust the tuning device rotatably and to adjust the inductance by endwise movement of the common operating means. 10. A radio tuner comprising a variable tuning device and an adjustable inductance, in combination with a common operating means arranged and connected to adjust both the tuning device and the inductance by a movement of said means in one plane and to adjust the inductance alone by movement of said means in a plane intersecting the first plane.

11. A radio control device comprising a fixed element a relatively movable element, and means for moving said relatively movable element in any one of a plurality of parallel planes and for moving such element bodily into any one of said planes regardless of its position in the plane from which it is moved, and means for limiting the extent of the bodily movement of said movable element while freely permitting such movement between prescribed limits.

12. In a radio control device, two stationary elements, two relatively movable elements cooperating respectively with said stationary elements, and means controlled .by a single control knob for giving one of said movable elements a movement in a single plane and for giving the other of the movable elements a movement within a plurality of planes.

13. In a radio control device, two stationary fim'elements, two relatively movable elements arranged to cooperate respectively with said stationary elements, and means controlled by a single control knob for moving one of said movable elements in a given plane and for moving the other of said movable elements in a plane intersecting said given plane while the first movable element remains stationary.

14. In a radio control device, two stationary elements, two relatively movable elements ariranged to cooperate respectively with said stationary elements, and means comprising a single control knob for moving both of said movable elements in parallel planes and for moving one of said movable elements in an intersecting plane 1 while the first element remains stationary.

15. A radio tuner comprising a variable tuning device and an adjustable coupling device, in combination with a common operating means arranged and connected to adjust both devices t L rotatedly and to adjust the coupling device by 755 ranged and connected to adjust both devices rotatedlys and; to adj'usttthe;v coupling: device by endwise movement while preventing. adjustment of the tuning device by endwise movement.

17. A radio. tuner including a variable tuning device. and a variable coupling device, a shaft mounted for. bothrotarysand endwise movements, and mechanical. connectionsbetween saidj shaft and said: devicesso arranged that both" devices.

respond to one of the said movements of said shaft, while one device only responds to the other movement of the shaft.

18. A radio tuner including a variable tuning device and a variable coupling device, a shaft mounted for both rotary movement and endwise movement, mechanical connections between one of said devices and said shaft such that the said one device responds to a rotary movement only of said shaft, and mechanical connections between the shaft and the other of said devices such that the said other device obtains an adjustment depending upon the rotative position of said shaft and upon the position into which the shaft is placed by endwise movement, whereby one of said devices is adjusted by rotary movement and the other device may be simultaneously adjusted to a combination of the two said movements of the shaft.

19. In a radio receiving set employing an amplifying device having an input circuit and an output circuit, a tuning device arranged to tune the input circuit, a coupling device arranged to variably couple the output circuit to the input circuit, and a common operating means having two separate movements and being arranged and connected to said tuning device and to said coupling device sothat one movement of the common operating means results in varying the tuning and the coupling in fixed relation and so that the said fixed relation may be altered by the other movement of the common operating means from time to time as desired.

20. In a regenerative radio receiving set employing a vacuum tube having a grid elemen and a plate element serving as terminals for input and output circuits respectively, a variable tuning device arranged to variably tune the input circuit, a variable coupling device arranged to variably couple the output circuit with the input circuit, and a common operating means circuit, a variable coupling device arranged to variably couple the output circuit with the input circuit, and a common operating means for simultaneously adjusting both devices in any one of a number of fixed relations and for predetermining any one of said fixed relations of adjustment.

22. In a radio receiving set including a tuning device arranged to tune the set to receive different wave lengths, an adjustable coupling device arranged to be adjusted independently of said tuning device, and a common operating means so arranged and connected to both devices that the preadjusted coupling is automatically altered as the receiving set is adjusted to re ceive different wave lengths, the relation between the tuning device and the coupling device being such that the maximum coupling with any adjustment of the coupling device always corresponds to the same adjustment of the tuning device.

23. In a radio set, a tuning device having an operating shaft, a coupling device comprising a fixed element and a movable element controlled by said shaft responsive to its manipulation to control the tuning device, whereby the tuning 

